Instrument dial lock



July 6, 1943. KESTER 2,323,608

INSTRUMENT DIAL LOCK Filed May 4, 1942 Patented July 6, 1943 INSTRUMENTDIAL LOCK Arthur S. Kester, Chicago,

111., assignor to Rauland Corporation, Chicago, 11., a corporation ofIllinois Application May 4, 1942, Serial No. 441,757

4 Claims.

This invention relates in general to instrument dials and moreparticularly to a manually controlled lock for precision, calibrateddials commonly used for controlling radio apparatus and laboratoryinstruments.

It is of extreme importance that dials of the above character beprovided with a locking means whereby a particular setting may besecured against accidental displacement and it is of further importancethat the locking means hold the dial securely without backlash andwithout exerting stresses in the dial or the dial shaft which mayinfluence the calibration of the instrument.

Dial locks previous to this invention were objectionable because of thecost of the precise nature of the construction required and in manycases the operation of the lock disturbed the desired setting of thedial or otherwise exerted stresses in the dial structure which causedchanges in calibration of the instrument to which they were attached.

In the present invention, the above objections are completely overcomeby the unique combination of simple elements which, by simplemanipulation, will rigidly secure a dial in any given fixed position.

A principal object of this invention is the provision of a manuallycontrolled dial locking elements cooperatively related to a control dialwhereby the said dial may be rigidly secured in any predeterminedposition of rotation without changing its position and otherwisestressing apparatus controlled by the dial.

Further objects and advantages of the invention will be apparent fromthe following description and drawing, in which Fig. l is a frontelevation of a conventional Vernier dial with lock attached.

Fig. 2 is a cross sectional plan view of the dial taken through sectionlines 2-2, shown Fig. 1.

Fig. 3 is an enlarged fragmentary cross sectional side view of the diallock taken through section lines 33, shown Fig. 1.

Fig. 4 is a fragmentary rear sectional view of the dial lock takenthrough section lines 4-4, shown Fig. 3.

One preferred embodiment of the invention is illustrated in the drawingin which Fig. l represents a conventional Vernier dial for the controlof a shaft which operates a calibrated, variable capacitor not shown.

Referring to Fig. 1, the fragmentary outline 2 represents a panel onwhich a fixed ring member 1 is secured by suitable screw means as shownand has engraved thereupon a conventional vernier scale. A rotatablecalibrated dial 3v is adapted to rotate in close proximity with theinner periphery of the ring member 1 and has integrally andconcentrically mounted thereon} an operating knob 4 which carries acrank handle 5 for providing convenient manual rotation of the dial.Locking knob 6 is provided to manually secure the dial 3 in anypredetermined position of rotation, the action of which will behereinafter described.

The cross sectional view Fig. 2 shows the end of a shaft '1 to which thedial 3 is attached. The shaft is journaled in bearing 8 and runs to theapparatus to be controlled, such as a variable capacitor or other devicerequiring precision rotational movement. The flanged hub 9 is pinned tothe shaft as shown and serves as a mounting medium for the rotativeparts of the dial and dial lock. A thin, flexible, circular plate ordisc 10 is held in concentric relation with shaft '1 between the face ofthe hub 9 and the inner face of the dial 3. The operating knob 4 ispositioned concentric and adjacent to the outer face of the dial bythree screws 1 l threaded into the flange of the hub 91. Thus when theoperating knob 4 is rotated by means of crank 5, the dial 3 and the disc10 will rotate concentrically with the shaft '1. A peripheral recess 12in the inside surface of the ring member 1 provides a space wherein theouter edge of the disc 10 will freely move without interference when thedial 3 is rotated.

The locking elements are clearly shown in Fig. 3 in their unlockedposition. A fiat spring 13 has one end secured to the panel 2 by rivets14-14. A threaded nut 15 is integrally secured to the free end of thespring 13 and positioned through an opening 16 in the panel 2 with theupper side portion of the nut in close proximity with the inner face ofthe disc 10. A look screw 11, integral with knob 6, is fitted in thethreaded hole of the nut 16. A hole through ring member I is providedfor the free movement of the screw 11 therein. A look ring 18 is securedto the end of screw 1'1 to limit the outward range of the screw.

Referring to the rear view Fig. 4, spring 13, nut 15, and screw 11 areshown in their relative positions in respect to the edge of disc 10,show ing the area of the nut 15 which laps over the edge of the disc 10for locking engagement which will be hereinafter described.

When the locking knob, Fig. 3, is rotated in the proper direction, itsshoulder will bear against the ring I at l9 and the screw I! will drawthe nut l5 toward the knob against the restraining action of spring l3and clamp the outer surface of the disc l0 tightly between the side faceof the nut and the inner surface of the ring member I, and thus lock thedial 3 against rotation.

It is to be noted that although the flexible disc I 0 will be slightlydisplaced, in an outward direction, from its normal path, this movementwill not appreciably transfer stresses to the dial or the dial shaft 7because of thehigh compliance of the disc in directions normal to itssurface.

It is also to be noted that there is no vector of force tending to turnthe disc about its center while the dial is being locked. It is furtherimportant to note that there will be a complete absence of lost motionbetween all the elements after locking because of the relatively highfrictional contact at the outer surfaces of the disc I and highresistance to movement in both the disc l0 and the spring l3 in adirection parallel to their planes.

The locking device herein described is suitable for use with instrumentcontrols that are adapted to move in linear paths as well as therotational type of control described by a simple physical change in theplate or disc Ill whereby the effective outer surface will maintain aconstant relation with the clamping surface of the threaded nut l5.

Having described my invention, I claim:

1. A device for locking an adjustable control member comprising astationary support means, a control member movable in a predeterminedpath with respect to said support means, a plate aflixed to said controlmember, said plate resilient in directions substantially at right anglesto its normal plane of movement, resilient lock means integrally securedat one end to said support means and positioned in close proximity withthe surface of said plate, manually operative clamping means coac tivelyrelated with said lock means and said support, whereby the operation ofsaid clamping means will move said lock means into frictional contactwith said plate and thence move said plate into frictional contact withsaid stationary support means to secure said plate and said controlmember in a fixed relation with said support means.

2. A device for locking an adjustable control member comprising astationary support means, a control member movable in a predeterminedpath with respect to said support means, a plate affixed to said controlmember, said plate resilient in directions substantially at right anglesto its normal plane of movement, spring lock means having one endsecured to said support means and its movable end positioned in closeproximity with one surface of the said plate, manually operativeclamping means coactively related with said lock means and said support,a fixed projection on said support means having an abut ting surfaceadjacent to the movable end of the said lock means, whereby theoperation of said clamping means will move said lock means intofrictional contact with the said one surface of said plate and flex saidplate with its opposite surface in frictional contact with saidprojection to secure said plate and said control member in a fixedrelation with said support means.

3. A device for locking a rotary control member comprising a stationarysupport means, a control member rotatably secured in fixed relation tosaid support means, a disc concentrically afiixed to said controlmember, said disc resilient in directions substantially at right anglesto its normal plane of rotation, resilient lock means secured to saidsupport means normally positioned in close proximity with one face ofsaid disc, a fixed lock means positioned on said support means having aworking surface adjacent to said resilient lock means, said resilientlock means and said fixed lock means normally positioned for the freemovement of the outer faces of said disc to move freely there-between,manually operative clamping means coactively related with said resilientlock means and said support, whereby the operation of said clampingmeans will move said resilient lock means into frictional contact withsaid disc and flex said disc into frictional contact with said fixedlock means to secure said plate and said control member in a fixedrelation with said support means.

4. A device for looking a rotary control member comprising a stationarysupport means, a control member rotatably secured in fixed relation tosaid support means, a disc resilient at right angles to its plane ofnormal rotation concentrically affixed to said control member, springlock means secured at one end to said support means and having onesurface of its free end in close proximity with the outer face of saiddisc and resilient only in a direction at right angles to the face ofsaid disc, manually operative screw means coactively related with saidlock means and said support means, whereby the operation of said screwmeans will clamp the outer faces of said disc between said lock meansand said support means to secure said disc and said control member in afixed relation with said support means.

ARTHUR S. I'CESTER.

